Question

If John travels 300 miles at a speed of 45 mph and
travels Another trip at 300 miles at 55 mph. Find the Avenge speed of the entine trip.

Answer 1

The average speed is 49.5 m/s.

Explanation:

As in the first trip, John travels 300 miles in 45 mph, then the time taken to cover this distance with 45 mph speed is

          $\text {Time}=\frac{\text {distance}}{\text {speed}}=\frac{300 \text { miles}}{45 \mathrm{mph}}=6.67 \mathrm{hr}$

Similarly, in second trip, the distance covered is 300 miles with speed of 55 mph.

Then, $\text {Time}=\frac{\text {distance}}{\text {speed}}=\frac{300 \text { miles }}{55 \mathrm{mph}}=5.45 \mathrm{hr}$

So average speed can be calculated by the ratio of sum of distance covered to sum of the time taken to cover the distances.

$Average speed = \frac{Sum of distance}{Sum of time}=\frac{300+300}{6.67+5.45}$

Hence, the average speed is 49.5 m/s.